xref: /freebsd/lib/libthr/arch/i386/include/pthread_md.h (revision aa1a8ff2d6dbc51ef058f46f3db5a8bb77967145)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2002 Daniel Eischen <deischen@freebsd.org>.
5  * Copyright (c) 2005 David Xu <davidxu@freebsd.org>.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 /*
31  * Machine-dependent thread prototypes/definitions.
32  */
33 #ifndef _PTHREAD_MD_H_
34 #define	_PTHREAD_MD_H_
35 
36 #include <stddef.h>
37 #include <sys/types.h>
38 #include <machine/tls.h>
39 
40 #define	CPU_SPINWAIT		__asm __volatile("pause")
41 
42 /* For use in _Static_assert to check structs will fit in a page */
43 #define	THR_PAGE_SIZE_MIN	PAGE_SIZE
44 
45 static __inline struct pthread *
46 _get_curthread(void)
47 {
48 	struct pthread *thr;
49 
50 	__asm __volatile("movl %%gs:%1, %0" : "=r" (thr)
51 	    : "m" (*(volatile u_int *)offsetof(struct tcb, tcb_thread)));
52 	return (thr);
53 }
54 
55 #endif
56